DORSAL INTEROSSEI OF HAND

Origin

1^st interosseous muscle – 1^st and 2^nd metacarpal bones.

2^nd interosseous muscle – 2^nd and 3^rd metacarpal bones.

3^rd interosseous muscle – 3^rd and 4^th metacarpal bones.

4^th interosseous muscle – 4^th and 5^th metacarpal bones.

Insertion

1^st interosseous muscle – 2^nd proximal phalanx and extensor expansion.

2^nd interosseous muscle – 3^rd proximal phalanx and extensor expansion.

3^rd interosseous muscle – 3^rd proximal phalanx and extensor expansion.

4^th interosseous muscle – 4^th proximal phalanx and extensor expansion.

Blood supply

Dorsal metacarpal artery, palmar metacarpal artery.

Nerve supply

Ulnar nerve – deep branch.

Action

The middle 3 fingers can spread away from the midline of the hand with the help of the dorsal interossei. It also helps in flexion of the metacarpophalangeal joints.

Disease/Injury

Excessive computer work can strain the dorsal interossei giving rise to pain.

Muscle Exercise

Finger abduction exercise must be performed to strengthen the dorsal interossei. A rubber band is worn around all the fingers. The fingers are then spread apart against the resistance offered by the rubber band. Hold for a few seconds and then bring fingers back to their original position. Do 10 repetitions.

Interesting Facts

In painful handshakes, it’s actually the interosseous muscles that are hurting.